The Assessment of Sleep Apnoea as a Risk Factor in Glaucoma

Background: The risk of developing open angle glaucoma increases in the presence of associated disorders such as hypertension, Diabetes mellitus and migraine. In recent years, sleep apnoea is also being investigated as a risk factor in the development of open angle glaucoma. Aim: To ascertain the significance of sleep apnoea as a risk factor in patients with glaucoma. Study Setting and Design: A non-randomised, cross sectional study was undertaken at an urban teaching hospital. Material and Methods: A sleep disturbance questionnaire and the Epworth sleepiness scale were used to screen the potential cases of sleep apnoea amongst 40 glaucomatous subjects, with both Primary Open Angle Glaucoma (POAG) and Normotensive Glaucoma (NTG), as well as 40 controls. Those which gave a positive response to the questionnaire were subjected to polysomnography for the diagnosis of sleep apnoea, with the calculation of the Apnoea Hypopnoea Index. The data was analysed by using the Chi-square test and the odds ratio calculations. Results: Positive responses to the sleep apnoea questionnaire were obtained from a total of twenty participants, 16 (40%) from the glaucoma Group and four (10%) were obtained from the control Group. In the glaucoma Group, ten (37.03%) of the 27 POAG individuals, and six (46.15%) of the 13 NTG cases showed significant positive responses to the questionnaire. Four subjects (10%) (1POAG, 3 NTG) from the glaucoma Group and one (2.5%) from the control Group were diagnosed to have sleep apnoea by polysomnography. The percentage of the sleep apnoea positive cases was higher among the NTG subjects (23.07%) than among the POAG subjects (3.7 %). This study had an odds ratio of 4.333 (> 1) and a p value of 0.382. Conclusion: Although the odds ratio was significant, this study did not find the association between sleep apnoea and glaucoma to be statistically significant.